A semiconductor device is supplied with power that needs for its operation from the outside. For example, a semiconductor memory device is supplied with power that needs for a memory cell array from the outside to perform read and write operations of data.
Chipset internal blocks of a semiconductor device require different power supply voltages respectively. Thus, a power supply circuit for supplying power to a semiconductor device converts an external voltage into at least one supply voltage to supply it to internal blocks of a semiconductor device. For example, a power supply circuit can be supplied with an external voltage and a ground voltage from the outside and then convert the external voltage and the ground voltage into a supply voltage such as a reference voltage, a peripheral voltage and a bulk voltage to supply it to internal blocks of a semiconductor device. To protect internal blocks from sudden power supply and sudden power interruption, a stable power supply technique is required.